Robot system equipped with video display apparatus that displays image of virtual object in superimposed fashion on real image of robot

ABSTRACT

A robot system according to the present invention comprises a control apparatus for controlling a robot, and a video display apparatus connected to the control apparatus. The video display apparatus comprises a display unit which displays an image of a real space containing the robot, in real time as the image is taken by a camera, and an augmented reality image processing unit which causes a virtual image of an end effector or robot peripheral equipment of the robot to be displayed on the display unit in superimposed fashion on a real image of the robot taken by the camera. According to the robot system, even when the end effector or the robot peripheral equipment is not present, a robot teaching task can be performed by assuming that they are present.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a robot system equipped with a videodisplay apparatus that displays an image of a virtual object insuperimposed fashion on a real image of a robot by using augmentedreality technology.

2. Description of the Related Art

In an industrial robot system installed at a manufacturing site, an endeffector, such as a robot hand or a machining tool, is attached to theforward end of a robot arm. Further, robot peripheral equipment, such asa belt conveyor or a rail-guided cart, is arranged in the vicinity ofthe robot.

However, at the stage of teaching the robot a sequence of actionsnecessary to accomplish a task, the end effector or the robot peripheralequipment may not yet be made available. In this case, the operator isunable to perform an appropriate robot teaching task until the endeffector or the robot peripheral equipment is made available.Accordingly, even when the end effector or the robot peripheralequipment is not available, it is desired to be able to perform therobot teaching task by assuming that they are present.

Augmented reality technology that allows a virtual image to be displayedin superimposed fashion on a real-time image is one technology that hasthe potential to be able to solve the above problem. In fact, apparatusconfigured to enhance operability at the time of a robot teaching taskby using such augmented reality technology have been proposed in recentyears.

For example, Japanese Patent No. 4850984 discloses a technique thatdisplays the operating scope of a robot operating in accordance with anoperation plan by superimposing the space on an image of a real robot byusing augmented reality. Further, Japanese Patent Application Laid-openNo. 2014-180707 discloses a technique that displays the motion path of arobot operating in accordance with an operation program by superimposingthe path on an image of a real robot by using augmented reality.

However, neither Japanese Patent No. 4850984 nor Japanese PatentApplication Laid-open No. 2014-180707 proposes techniques for displayingan image of an end effector or robot peripheral equipment as describedabove, in superimposed fashion on an image of a real robot by usingaugmented reality technology.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a robot system that,even in the absence of an end effector or robot peripheral equipment,can perform a robot teaching task by assuming that they are present.

According to a first aspect of the present invention, there is provideda robot system comprising: a control apparatus for controlling a robot;and a video display apparatus connected to the control apparatus,wherein the video display apparatus comprises: a display unit whichdisplays an image of a real space containing the robot, in real time asthe image is taken by a camera; and an augmented reality imageprocessing unit which causes a virtual image of an end effector or robotperipheral equipment of the robot to be displayed on the display unit insuperimposed fashion on a real image of the robot taken by the camera.

According to a second aspect of the present invention, the video displayapparatus in the robot system of the first aspect further comprises avirtual object image generating unit which, based on relative positionand angle between the robot and the camera, generates the virtual imageof the end effector or the robot peripheral equipment to be displayed insuperimposed fashion on the real image of the robot taken by the camera.

According to a third aspect of the present invention, the augmentedreality image processing unit in the robot system of the first or secondaspect is configured to cause the virtual image of the end effector orthe robot peripheral equipment to be displayed on the display unit whilemoving the virtual image based on position/orientation data of the robotbeing controlled by the control apparatus or on a pseudo-signal receivedfrom the control apparatus.

According to a fourth aspect of the present invention, the controlapparatus in the robot system of any one of the first to third aspectincludes a teach operation panel which is used to perform operation toteach the robot.

According to a fifth aspect of the present invention, the video displayapparatus in the robot system of any one of the first to fourth aspectis a head-mounted display equipped with the camera.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features, and advantages of the presentinvention will become more apparent from the detailed description of thetypical embodiments given below with reference to the accompanyingdrawings, wherein:

FIG. 1 is a block diagram showing a robot system according to oneembodiment of the present invention;

FIG. 2 is a flowchart illustrating an operation flow performed whendisplaying an image of a virtual object by superimposing it on a realimage of a robot;

FIG. 3 is a diagram schematically illustrating how a first embodiment isimplemented;

FIG. 4 is a diagram schematically illustrating how images displayed on adisplay unit of an augmented reality-capable display change as the robotis operated; and

FIG. 5 is a diagram schematically illustrating how a second embodimentis implemented.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below withreference to the drawings. Throughout the drawings, the same componentmembers or functional elements are designated by the same referencenumerals. Further, for ease of understanding, the members or elements inthe drawings are not necessarily drawn to scale.

FIG. 1 is a block diagram showing a robot system according to oneembodiment of the present invention. As shown in FIG. 1, the robotsystem 10 of the present embodiment comprises a robot 11, a robotcontrol apparatus 12 for controlling the robot 11, an augmentedreality-capable display 13 as a video display apparatus which isconnected to the robot control apparatus 12, and a teach operation panel1 which is connected to the robot control apparatus 12 and used toperform operation to teach the robot 11.

The robot 11 is, for example, a vertically articulated manipulator.Servo motors (not shown) are provided, one for each articulated axis ofthe robot 11. The robot 11 is further provided with a position detectionsensor 15, for example, a pulse encoder, for detecting the axialposition (rotation angle) of each servo motor.

A mounting portion (not shown) to which a detachable end effector, suchas a robot hand or a machining tool, is mounted is provided at theforward end of the arm of the robot 11.

The robot control apparatus 12 has the function of generating a controlsignal and driving the robot 11 in accordance with an operation program.The robot control apparatus 12 not only outputs the control signal tothe robot 11 but receives signals from the augmented reality-capabledisplay 13 and the teach operation panel 14.

The robot control apparatus 12 includes a program holding unit 16 whichholds the operation program of the robot 11, and a position/orientationdata generating unit 17 which generates position/orientation datarelating to the robot 11.

The operation program of the robot 11 is input from the teach operationpanel 14 to the program holding unit 16. The operation program held inthe program holding unit 16 can be rewritten from the teach operationpanel 14.

The robot control apparatus 12 supplies a position command to the servomotor in accordance with the operation program held in the programholding unit 16, and controls the servo motor so that the position ofthe servo motor detected by the position detection sensor 15 matches theposition command. The robot 11 is thus controlled to operate inaccordance with the operation program held in the program holding unit16.

Based on a servo motor position signal output from the positiondetection sensor 15, the position/orientation data generating unit 17generates position/orientation data relating to the robot 11, andoutputs the generated data to the augmented reality-capable display 13.

When performing a robot teaching task, the operator operates the robot11 from the teach operation panel 14 while viewing the display producedthrough the augmented reality-capable display 13. During this process, asequence of actions necessary to accomplish a desired task is taught tothe robot 11 from the teach operation panel 14 via the robot controlapparatus 12.

When performing such a robot teaching task, there are cases where theend effector, such as a robot hand or a machining tool, to be attachedto the forward end of the arm of the robot 11 cannot be made available.There are also cases where the robot peripheral equipment, such as abelt conveyor or a rail-guided cart for conveying workpieces, cannot bearranged in the vicinity of the robot 11. To address such cases, therobot system 10 of the present embodiment is configured so that the endeffector or the robot peripheral equipment can be displayed as a virtualimage on the augmented reality-capable display 13.

More specifically, as shown in FIG. 1, the augmented reality-capabledisplay 13 comprises a camera 18 for shooting a real space containingthe robot 11, a display unit 19 for displaying an image of the realspace containing the robot 11, in real time as the image is taken by thecamera 18, and a computer 20.

The augmented reality-capable display 13 is, for example, a head-mounteddisplay (see FIGS. 3 and 5). In this case, the display unit 19preferably has display screens, each about the size of a spectacle lens,arranged so as to correspond with the two eyes of a human. The augmentedreality-capable display 13 is not limited to a head-mounted display, theonly requirement being that the operator be able to view the imagecaptured by the camera 18, while holding the teach operation panel 14 inhis hand.

The computer 20 incorporated in the augmented reality-capable display 13comprises, as shown in FIG. 1, a camera position/orientation estimatingunit 21, a virtual object data holding unit 22, a virtual object imagegenerating unit 23, and an augmented reality image processing unit 24.However, the virtual object data holding unit 22 and the virtual objectimage generating unit 23 may be incorporated in the robot controlapparatus 12.

The camera position/orientation estimating unit 21 estimates theposition and angle (orientation) of the camera 18 relative to the robot11 to be taken by the camera 18.

The virtual object data holding unit 22 holds data relating to a virtualobject that is not present in the real space in which the robot 11 islocated. The virtual object data is input from the teach operation panel14 to the virtual object data holding unit 22. The virtual object datais data representing the three-dimensional shape and location of the endeffector, the robot peripheral equipment, or the like.

The virtual object data held in the virtual object data holding unit 22is input to the virtual object image generating unit 23. Further, thedata representing the relative position and angle (relative position andorientation) between the robot 11 and the camera 18 is input from thecamera position/orientation estimating unit 21 to the virtual objectimage generating unit 23.

Based on the virtual object data and the data representing the relativeposition and angle between the robot 11 and the camera 18, the virtualobject image generating unit 23 generates the image of the virtualobject that matches the real image of the robot 11 taken by the camera18. Here, when the relative position and angle between the robot 11 andthe camera 18 changes, the image of the virtual image is changedaccordingly to match the real image of the robot 11.

Image information of the virtual object generated by the virtual objectimage generating unit 23 is input to the augmented reality imageprocessing unit 24.

Further, the position/orientation data being generated during theoperation of the robot 11 is input from the position/orientation datagenerating unit 17 in the robot control apparatus 12 to the augmentedreality image processing unit 24 via the computer 20. The real imageinformation of the robot 11 taken by the camera 18 is also input to theaugmented reality image processing unit 24.

Then, based on the position/orientation data of the robot 11, theaugmented reality image processing unit 24 superimposes the image of thevirtual object generated by the virtual object image generating unit 23onto the real image of the robot 11 for display on the display unit 19.During the operation of the robot 11, it is preferable that the imagedata of the virtual object to be superimposed on the real image of therobot 11 is updated at predetermined intervals of time, based on theposition/orientation data of the robot 11 in operation.

FIG. 2 is a flowchart illustrating an operation flow performed whendisplaying the image of the virtual object, such as the end effector orthe robot peripheral equipment, by superimposing it on the real image ofthe robot 11 taken by the camera 18.

As shown in FIG. 2, first the augmented reality-capable display 13determines whether or not the real image of the robot 11 has beencaptured via the camera 18 (step S11).

If it is determined that the real image of the robot 11 has beencaptured, the camera position/orientation estimating unit 21 in theaugmented reality-capable display 13 estimates the relative position andangle between the robot 11 and the camera 18 (step S12).

After the above step S12, the position/orientation data generating unit17 in the robot control apparatus 12 outputs the position/orientationdata of the robot 11 to the augmented reality-capable display 13 (stepS13).

Next, the augmented reality-capable display 13 displays the image of thevirtual object, such as the end effector or the robot peripheralequipment, by superimposing it on the real image of the robot 11 takenby the camera 18 (step S14). In this case, the image of the virtualobject is created based on the relative position and angle between therobot 11 and the camera 18 and, based on the position/orientation dataof the robot 11, the image of the virtual object is superimposed on thereal image of the robot 11, as earlier described.

Further, the augmented reality-capable display 13 determines whether ornot the superimposed display image, that is, the image of the virtualobject superimposed on the real image of the robot 11, needs to be moved(step S15).

When a change occurs in the position/orientation data of the robot 11that the position/orientation data generating unit 17 outputs to theaugmented reality-capable display 13, the augmented reality-capabledisplay 13 determines in the above step S15 that the “YES” branch shouldbe taken.

If it is determined in the above step S15 that the “YES” branch shouldbe taken, the augmented reality-capable display 13 moves thesuperimposed display image (step S16). To accomplish this, thesuperimposed display image data is updated at predetermined intervals oftime, based on the position/orientation data of the robot 11 inoperation.

An example in which an image of a virtual end effector is superimposedon the real image of the real-world robot 11 (hereinafter called thefirst embodiment) will be described in detail below.

Embodiment 1

FIG. 3 is a diagram schematically illustrating how the first embodimentis implemented.

When performing a robot teaching task, the operator wears the augmentedreality-capable display 13, as shown in FIG. 3, and visually recognizesthe robot 11 installed at a given place. At this point, the endeffector, such as a robot hand or a machining tool, is not yet attachedto the forward end of the arm of the robot 11. Likewise, the robotperipheral equipment, such as a belt conveyor or a rail-guided cart forconveying workpieces, is not yet arranged in the vicinity of the robot11.

In such a real-world environment, the augmented reality-capable display13 captures the image of the real-world environment containing the robot11 taken by the camera 18 (see arrow A in FIG. 3).

Next, the camera position/orientation estimating unit 21 incorporated inthe augmented reality-capable display 13 estimates the relative positionand angle between the robot 11 and the camera 18. The reason for this isthat when superimposing the image of the virtual end effector on thereal image R1 of the real-world robot 11, the image R2 of the virtualend effector must be displayed in a proper orientation and position.

In the first embodiment, the relative position and angle between therobot 11 and the camera 18 is estimated in the following manner.

First, the robot 11 in various stationary orientations are taken fromvarious viewpoints by the camera 18, and a plurality of image models ofthe robot 11 is recorded in the camera position/orientation estimatingunit 21. At this time, the relative position and angle between the robot11 and the camera 18 is also recorded for each acquired image model ofthe robot 11.

After that, when the real image R1 of the real-world robot 11 iscaptured into the augmented reality-capable display 13, as describedabove, the real image R1 of the real-world robot 11 thus captured iscompared with the plurality of prerecorded image models M₁, M₂, . . . ,M_(n) of the robot 11 (see arrow B in FIG. 3) to determine which imagemodel is closest to the captured image. Then, the cameraposition/orientation estimating unit 21 assumes that the relativeposition and angle between the robot 11 and the camera 18, associatedwith the closest image model, represents the position and angle of thecamera 18 relative to the robot 11 currently being taken by the camera18.

Next, the camera position/orientation estimating unit 21 notifies therobot control apparatus 12 that the relative position and angle betweenthe robot 11 and the camera 18 has been estimated (see arrow C in FIG.3).

Thereupon, the position/orientation data generating unit 17 in the robotcontrol apparatus 12 transmits the present position/orientation data ofthe robot 11 to the augmented reality-capable display 13 (see arrow D inFIG. 3).

Next, the virtual object image generating unit 23 incorporated in theaugmented reality-capable display 13 generates the image R2 of thevirtual end effector that matches the real image R1 of the robot 11currently being taken by the camera 18. Here, the image R2 of thevirtual end effector is generated based on the virtual object datastored and held in the virtual object data holding unit 22, i.e., thedata representing the three-dimensional shape, etc., of the endeffector, and on the relative position and angle between the robot 11and the camera 18 estimated as described above. More specifically, theimage R2 of the virtual end effector is generated as an image having aproper orientation, position, and size with respect to the forward endof the arm contained in the real image R1 of the robot 11 taken by thecamera 18.

Then, the augmented reality image processing unit 24 incorporated in theaugmented reality-capable display 13 causes the image R2 of the virtualend effector generated by the virtual object image generating unit 23 tobe displayed on the display unit 19 in such a manner as to be added atthe forward end of the arm in the real image R1 of the robot 11 taken bythe camera 18 (see arrow E in FIG. 3). In this case, the position of theforward end of the arm in the real image R1 of the robot 11 isidentified based on the position/orientation data of the robot 11received from the robot control apparatus 12 and the relative positionand angle between the robot 11 and the camera 18.

FIG. 4 is a diagram schematically illustrating how images displayed onthe augmented reality-capable display 13 change as the robot 11 isoperated.

When performing a robot teaching task, the operator operates the robot11 by using the teach operation panel 14. Since the position/orientationof the robot 11 changes during operation, the real image R1 of the robot11 displayed on the display unit 19 changes accordingly, as shown inFIG. 4. Then, based on the changing position/orientation data of therobot 11, the augmented reality image processing unit 24 updates thedata of the image R2 of the virtual end effector to be displayed nearthe forward end of the arm in the real image R1 of the robot 11. Here,it is preferable that the image R2 of the virtual end effector isgenerated by the virtual object image generating unit 23 in real time asthe real image R1 of the robot 11 changes. In this way, the image R2 ofthe virtual end effector (the image portion 25 encircled by a dashedline in FIG. 4) displayed near the forward end of the arm in the realimage R1 of the robot 11 can be made to move as the real image R1 of therobot 11 changes.

According to the first embodiment described above, even when the endeffector is not attached to the forward end of the arm of the robot 11,the robot teaching task can be performed using the augmentedreality-capable display 13 by assuming that the end effector is present.Furthermore, since a head-mounted display is used as the augmentedreality-capable display 13, the operator can operate the teach operationpanel 14 while viewing the image captured by the camera 18 and displayedon the display unit 19.

Next, an example in which an image of virtual robot peripheral equipmentis superimposed on the real image of the real-world robot 11(hereinafter called the second embodiment) will be described in detailbelow.

Embodiment 2

FIG. 5 is a diagram schematically illustrating how the second embodimentis implemented.

When performing a robot teaching task, the operator wears the augmentedreality-capable display 13, as shown in FIG. 5, and visually recognizesthe robot 11 installed at a given place. At this point, the endeffector, such as a robot hand or a machining tool, is not yet attachedto the forward end of the arm of the robot 11. Likewise, the robotperipheral equipment, such as a belt conveyor or a rail-guided cart forconveying work, is not yet arranged in the vicinity of the robot 11.

In such a real-world environment, the augmented reality-capable display13 captures the image of the real-world environment containing the robot11 taken by the camera 18 (see arrow F in FIG. 5). However, in thesecond embodiment, at least one marker 26 is attached to the surface ofthe robot 11. It is preferable that the marker 26 has a prescribed shapeor pattern that can be recognized as an image by the camera 18.

Next, the camera position/orientation estimating unit 21 incorporated inthe augmented reality-capable display 13 estimates the relative positionand angle between the robot 11 and the camera 18. The reason for this isthe same as that described in the first embodiment.

In the second embodiment, the relative position and angle between therobot 11 and the camera 18 is estimated in the following manner.

A plurality of markers 26 is attached to the surface of the robot 11installed in the real space, and an image of each marker 26 is capturedby the camera 18. The position of each marker 26 in the real space isknown. Accordingly, the position and orientation (angle) of the camera18 in the real space coordinate system can be calculated from theposition of each marker 26 projected on the image coordinate system ofthe camera 18. By this calculation, the camera position/orientationestimating unit 21 estimates the relative position and angle between therobot 11 and the camera 18. It is preferable that the image model of thedesired robot peripheral equipment is associated with the position ofeach marker 26. Then, based on the position and orientation (angle) ofthe camera 18 in the real space coordinate system, data representing theimage model of the desired robot peripheral equipment can be displayedin superimposed fashion on the desired position in the real image of therobot 11.

Next, the camera position/orientation estimating unit 21 notifies therobot control apparatus 12 of the thus calculated relative position andangle between the robot 11 and the camera 18 (see arrow G in FIG. 5). Inthe second embodiment, it is assumed that, unlike the configurationshown in FIG. 1, the virtual object data holding unit 22 and the virtualobject image generating unit 23 are incorporated in the robot controlapparatus 12.

The virtual object image generating unit 23 incorporated in the robotcontrol apparatus 12 generates the image R3 of the virtual robotperipheral equipment, for example, a belt conveyor, to be added to thereal image R1 of the robot 11 currently being taken by the camera 18.Here, the image R3 of the virtual robot peripheral equipment isgenerated based on the virtual object data stored and held in thevirtual object data holding unit 22, i.e., the data representing thethree-dimensional shape, etc., of the robot peripheral equipment, and onthe relative position and angle between the robot 11 and the camera 18calculated as described above. More specifically, the image R3 of thevirtual robot peripheral equipment is generated as an image having aproper orientation, position, and size with respect to the real image R1of the robot 11 taken by the camera 18.

Next, the robot control apparatus 12 transmits the image R3 of thevirtual robot peripheral equipment generated by the virtual object imagegenerating unit 23 to the augmented reality image processing unit 24incorporated in the augmented reality-capable display 13 (see arrow H inFIG. 5).

Then, the augmented reality image processing unit 24 causes the image R3of the virtual robot peripheral equipment generated by the virtualobject image generating unit 23 to be displayed on the display unit 19in superimposed fashion on the real image R1 of the robot 11 taken bythe camera 18 (see arrow I in FIG. 5). In this case, the position atwhich the image R3 of the virtual peripheral equipment of the robot isdisplayed in superimposed fashion is identified based on the position ofthe marker 26 projected on the image coordinate system of the camera 18and the relative position and angle between the robot 11 and the camera18.

Preferably, the following method is employed to move the image R3 of thevirtual robot peripheral equipment, for example, a belt conveyor,displayed in superimposed fashion on the real image of the robot 11.First, a plurality of moving images representing incremental movementsof the movable belt portion of the virtual conveyor is created inadvance and recorded in the virtual object data holding unit 22. Therobot control apparatus 12 is configured to be able to generate apseudo-signal for controlling the virtual belt conveyor and output it tothe augmented reality-capable display 13 at a desired time. Then, inresponse to the input of the pseudo-signal from the robot controlapparatus 12, the augmented reality-capable display 13 displays themoving images of the movable belt portion at predetermined intervals oftime, each in a proper orientation, position, and size and in asuperimposed fashion with respect to the real image of the robot 11.

According to the second embodiment described above, even when the robotperipheral equipment, such as a belt conveyor, is not actually arrangedin the vicinity of the robot 11, the robot teaching task can beperformed using the augmented reality-capable display 13 by assumingthat the robot peripheral equipment is present. Furthermore, since ahead-mounted display is used as the augmented reality-capable display13, the operator can operate the teach operation panel 14 while viewingthe image captured by the camera 18 and displayed on the display unit19.

While the present invention has been described with reference to thetypical embodiments thereof, it will be understood by those skilled inthe art that the above and various other changes, omissions, andadditions can be made to the above embodiments without departing fromthe scope of the present invention. It will also be recognized thatsuitably combining the above embodiments falls within the scope of thepresent invention.

ADVANTAGEOUS EFFECT OF THE INVENTION

According to the first, second, third, and fourth aspects of the presentinvention, even when the end effector or the robot peripheral equipmentis not available for the robot, the robot teaching task can be performedusing the video display apparatus by assuming that the end effector orthe robot peripheral equipment is present.

According to the fifth aspect of the present invention, the operator canoperate the teach operation panel while viewing the image captured bythe camera and displayed on the display unit.

The invention claimed is:
 1. A robot system comprising: a controlapparatus for controlling a robot; and a video display apparatusconnected to the control apparatus, the video display apparatusincluding: a display unit configured to display, in real time, an imageof a real space containing the robot taken by a camera; a cameraposition and orientation estimating unit configured to estimate arelative position and an angle between the robot and the camera based oncomparison between the image of the real space and prerecorded imagemodels; an augmented reality image processing unit configured to cause avirtual image of an end effector attached to the robot to be displayedon the display unit in superimposed fashion on a real image of the robottaken by the camera, the virtual image being generated based on therelative position and the angle estimated by the camera position andorientation estimating unit, wherein the augmented reality imageprocessing unit is configured to cause the virtual image to be displayedon the display unit while moving the virtual image, based on positionand orientation data of the robot being controlled by the controlapparatus.
 2. The robot system according to claim 1, wherein the videodisplay apparatus further comprises a virtual object image generatingunit configured to, based on relative position and angle between therobot and the camera, generate the virtual image to be displayed insuperimposed fashion on the real image.
 3. The robot system according toclaim 1, wherein the control apparatus includes a teach operation panelwhich is used to perform operation to teach the robot.
 4. The robotsystem according to claim 1, wherein the video display apparatus is ahead-mounted display equipped with the camera.
 5. A robot systemcomprising: a control apparatus for controlling a robot; and a videodisplay apparatus connected to the control apparatus, the video displayapparatus including: a display unit configured to display, in real time,an image of a real space containing the robot taken by a camera; acamera position and orientation estimating unit configured to estimate arelative position and angle between the robot and the camera; anaugmented reality image processing unit configured to cause a virtualimage of an end effector attached to the robot to be displayed on thedisplay unit in superimposed fashion on a real image of the robot takenby the camera, the virtual image being generated based on the relativeposition and angle estimated by the camera position and orientationestimating unit; and a virtual image movement determination unitconfigured to determine that the virtual image needs to be moved, when achange occurs in position and orientation data of the robot beingcontrolled by the control apparatus wherein, the augmented reality imageprocessing unit is configured to cause the virtual image to be displayedon the display unit while moving the virtual image, based on theposition and orientation data.
 6. A robot system comprising: a controlapparatus for controlling a robot; and a video display apparatusconnected to the control apparatus, the video display apparatusincluding: a display unit configured to display, in real time, an imageof a real space containing the robot taken by a camera; a cameraposition and orientation estimating unit configured to estimate arelative position and angle between the robot and the camera; anaugmented reality image processing unit configured to cause a virtualimage of an end effector attached to the robot to be displayed on thedisplay unit in superimposed fashion on a real image of the robot takenby the camera, the virtual image being generated based on the relativeposition and angle estimated by the camera position and orientationestimating unit; and a virtual image movement determination unitconfigured to determine whether or not the virtual image superimposed onthe real image needs to be moved based on position and orientation dataof the robot being controlled by the control apparatus, wherein upondetermination that the virtual image superimposed on the real imageneeds to be moved, the augmented reality image processing unit isconfigured to move the virtual image and cause the virtual image to bedisplayed on the display unit while moving the virtual image.
 7. Therobot system according to claim 6, wherein, when the virtual imagemovement determination unit determines that the virtual image needs tobe moved, the augmented reality image processing unit updates thevirtual image superimposed on the real image so as to move the virtualimage, based on the position and orientation data.